I think I'm using the poly bridge tool incorrectly, as I keep getting a “source does not have boundary chain” error. I can poly bridge faces just fine, but when it comes to creating flat bridges in between edges, I appear to be missing a step.

Can anyone say if flat edge bridges even work? I can't seem to find any tutorials on it. The only one that SideFX provides displays face bridging.

Try to make a edge group from your flat primitives by Group Promote and then use newly edge group in PolyBridge. But this is weird that PolyBridge can't bridge without this step. Houdini should be renamed to Puzzle 3D

I just got this error today. It was because my groups were on primitives instead of edges.